The present invention relates to a method for manufacturing an intake muffler, particularly for compression circuits for refrigeration systems and the like.
Conventionally an air intake device, which acts as silencer and as cooling system, is used for each compressor in compression circuits.
This device, better known as intake muffler, consists of two parts: a base, in which a labyrinth-like path is molded, and a cover; said parts are assembled in order to obtain a hermetic casing.
In view of the particular operating conditions, since the intake is transmitted to capillary ducts, the muffler must be provided so that in addition to ensuring perfect tightness it has no flash which, as a consequence of its separation, might start circulating and obstruct said capillary passages.
Intake mufflers are currently manufactured in two parts which are joined by ultrasonic welding. Although this type of welding occurs in controlled conditions as regards the profile of the two parts to be coupled, the shape of the sonotrode and the frequency and intensity of the welding action, nonetheless some of the welded parts have flash along their inside and outside perimeters.
This is due to the fact that producing a perfect seal and the absence of flash are two mutually contrasting requirements, since a lower welding intensity, and therefore the absence of flash, is matched by a poor seal of the joint provided between the two assembled parts.
On the contrary, higher welding intensity and therefore better tightness of the joint is matched by the presence of internal and external perimetric flash.
It should be observed that internal flash is the most damaging, since it cannot be detected once the muffler has been assembled, and is also responsible for any obstructions of the capillary passages if it breaks off.
Optimization of the ultrasonic welding joint has been sought by designing various shapes of the parts to be assembled and by forming on the perimeter of the cover a rim for containing any flash produced.
These solutions, however, are unsatisfactory, both because the flash persists and because the rim for containing said flash breaks during ultrasonic welding.
Another conventional solution for mutually assembling the cover and the base of the muffler provides for the mutual interlocking of the two parts by means of teeth formed in the plastic; in this manner the muffler is not pressure-tight.
Another conventional solution provides for the insertion, between the base and the cover, of a third element made of rubber-like material which, when compressed, provides at least some sort of pressure-tightness.
The aim of the present invention is to provide a method for manufacturing an intake muffler for compression circuits for refrigeration systems and the like which combines optimum tightness with substantially complete absence of flash.
Within the scope of this aim, an object of the present invention is to provide a method for manufacturing an intake muffler for compression circuits for refrigeration systems and the like in which internal flash is fully eliminated.
Another object of the present invention is to provide a method for manufacturing an intake muffler for compression circuits for refrigeration systems and the like in which the construction method according to the invention is provided by modifying molds that are currently used.
Another object of the present invention is to provide a method for manufacturing an intake muffler for compression circuits for refrigeration systems and the like which is highly reliable, relatively easy to manufacture and at low costs.
This aim, these objects and others which will become apparent hereinafter are achieved by a method for manufacturing an intake muffler, particularly for compression circuits for refrigeration systems and the like, comprising the steps of:
molding a cover and a base of an intake muffler; and
mutually assembling said base and said cover in a mold inside which a perimetric profile is formed, being adapted to form a retention joint which is molded perimetrically at the edge where said base and said cover are mutually coupled.
This aim, these objects and others are also achieved by an intake muffler for compression circuits, particularly for refrigeration systems and the like, comprising a base provided with air passage channels and with a cover which is meant to be coupled to said base, characterized in that it comprises a retention joint which is molded around the perimetric seam between said base and said cover.